Field of the Invention
The present invention relates to a process control system constructed at a plant, a factory, or the like, and a managing method therefor.
Priority is claimed on Japanese Patent Application No. 2012-227845, filed Oct. 15, 2012, the content of which is incorporated herein by reference.
Description of the Related Art
All patents, patent applications, patent publications, scientific articles, and the like, which will hereinafter be cited or identified in the present application, will hereby be incorporated by reference in their entirety in order to describe more fully the state of the art to which the present invention pertains.
Conventionally, a process control system is constructed at a plant, a factory, and the like (hereinafter referred to collectively as ‘plant’) and controls various kinds of state quantities in the industrial process (e.g. pressure, temperature, flow rate, etc.), thereby achieving a high degree of automation. The process control system includes on-site devices known as field devices (measuring devices and operating devices), controllers for controlling the operation of these field devices, and a higher-level managing apparatus that manages and controls the field devices and the controllers, which are connected via a communications means.
In such a process control system, process values acquired by the field devices (e.g. measurements of pressure, temperature, flow rate, etc.) are collected by the controllers, and, under the management of the upper managing apparatus, the various state quantities are controlled by operating the field devices in accordance with the process values collected by the controllers. Information indicating the states of the controllers and the like are collected by the upper managing apparatus, and the process control system is managed on the basis of this collected information.
Hitherto, in most process control systems, a controller and field devices with analog communication functions were connected via analog transmission lines (e.g. transmission lines used for transmitting signals of 4 to 20 mA). In contrast, in many recent process control systems, to achieve high functionality, digitized field devices and a controller are connected by a wired or wireless network (e.g. a field network).
Japanese Patent (Granted) Publication No. 4326768 discloses a technology for diagnosing the soundness of a plant network installed at a power plant or the like. Specifically, in a technology disclosed in Japanese Patent (Granted) Publication No. 4326768, the soundness of the plant network is diagnosed by connecting a data collection means and a test means to a plant network which is connected to a control device, collecting all frames transmitted on the plant network in the data collection means, and testing the frames in the test means by comparing frames transmitted in a regular cycle with frame reference information stored beforehand.
In the conventional process control system described above, since the field devices and the controllers are basically connected one-to-one via analog transmission lines, the connection between the field devices and the controllers is simple. Therefore, if the process control system fails in some way (e.g. if there is a communication failure between a field device and a controller), it is easy to identify the location of the failure.
In contrast, in the recent process control system described above, the field devices and the controller are connected via a network. This network is configured from, for example, a plurality of network switches connected in a cascade, and, since the scale of the network increases according to the number of field devices and controllers, the connection of the field devices and controllers is more complex than in the conventional systems. Devices supplied from various vendors (field devices, controllers, etc.) can also be connected to this network.
When a network of connected field devices and controllers becomes complex and devices supplied from various vendors are connected to it in this way, it is difficult to manage the overall process control system including the network and the devices constituting the process control system. This leads to a problem that, when there is a failure in the network or in a device constituting the process control system, there is a danger that the failure will go undetected and control will be performed based on erroneous process values.
Even if a failure in the network or in a device constituting the process control system is detected, there is a problem that it is difficult to identify the location and cause of the failure, for the following reasons:
(1) Non-Uniformity of Information Coding Systems
Due to multi-vending of devices and the like, the coding system for information indicating the states of the devices constituting the process control system may differ for each type of device. Consequently, even if the same failure is detected in different types of devices, since the information codes indicating the failure are different, a dictionary or the like is needed to decipher them. Conventionally, a higher device carries out this deciphering process using a dictionary or the like, and since every change or expansion of the codes requires a change/addition to the dictionary and the like, there are considerable obstacles to easily ascertaining the type of the failure.
(2) Insufficient Route Information
Conventionally, many of the devices that constitute a network (e.g. network switches, gateways, linking devices, etc.) cannot transmit their route information and state. Moreover, even if the devices include this function, when there are restrictions due to the outdated architecture of the process control system and such like, it is not possible to acquire sufficient route information of the network and this function cannot be adequately utilized, or this function is not easy to utilize and there are difficulties in correctly identifying failures that occur in the network.